1. Field of the Invention
The present invention relates generally to Ethernet systems and methods and, more particularly, to a system and method for using an alternative wire pair for communication on initial wire pair failure.
2. Introduction
Conventional physical layer devices (PHYs) can support a variety of transmission rates. For example, a triple-speed PHY can be designed to support 1 Gbit/s, 100 Mbit/s and 10 Mbit/s operation modes. Here, 1 Gbit/s operation mode would require the use of four wire pairs, while the 100 Mbit/s and 10 Mbit/s operation modes would require the use of two wire pairs. As would be appreciated, quad-speed PHYs can also be designed to support 10 G or higher operation modes.
Upon startup, a pair of devices would use an autonegotiation procedure to choose common transmission parameters, such as speed and duplex mode. In this process, a connected pair of devices would each declare its capabilities. The two devices would then choose the best possible mode of operation that is shared by the two devices. With respect to speed, the two devices would typically choose the highest speed supported by both devices. For example, if both devices are triple-speed PHYs, then the autonegotiation process could settle on 1 Gbit/s as the chosen mode of operation.
Once the link has been established, one of the concerns in network management is failure recovery. As Ethernet links can use four wire pairs, a failure in any of the four wire pair communications can disrupt Ethernet link operation. Detecting and responding to such failures is therefore a key element in providing maximum network efficiency and integrity. What is needed therefore is a mechanism that enables the Ethernet system to account for failures in an active manner during system operation.